1. Field of the Invention
The present disclosure relates to an apparatus and a method for increasing evaporation rates of solutions within sample containers subjected to a drying gas flowing into the sample container.
2. Background Information
Sample concentrators are prevalent in processing liquid solutions containing a sample material or materials of interest. Materials of interest are typically synthesized, modified, and purified, in solution-based process steps. To recover these dissolved non-volatile materials as dry powders, or to increase the concentration of compounds, vacuum centrifuges, freeze drying, and blow down concentrators are commonly used.
Vacuum concentrators and freeze dryers generally require a powerful vacuum pump to produce the low levels of ambient pressure necessary to promote the ejection and escape of solvent molecules from the surface of the solution. These solvent molecules migrate to the lower concentration region of a cold trap solvent collection container and condense into liquid and/or freeze into ice.
Blow-down concentrators generally create a continuous flow of a small amount of gas onto the surface of the liquid solution. The gas flow may promote the escape of solvent molecules from the solution container that are then carried away in the flow of gas out an exhaust port. Flow rates may be typically 1 or 2 liters/minute to prevent loss of solution or dry compound from the sample container.
FIG. 1 illustrates a jet of blow-down gas directed 2 into half of the opening of a conventional test tube containing liquid 8 to be evaporated. Because the neck of the tube directs the incoming and exiting streams of gas into the same region, turbulent interaction 4 occurs, and the gas exits 6 without nearing the surface 10 of the liquid 8. A laminar high volume flow of blow-down gas striking the surface 10 of the liquid is the goal, but it may not be achieved due to the turbulence. In FIG. 1, the liquid surface is vertical, as the test tube is being depicted in an operating centrifuge meant to retain the liquid and sample within the container.